Maize chlorotic dwarf virus and resistance thereto

ABSTRACT

Methods and materials are provided to isolate the coat protein genes from maize chlorotic dwarf virus. One or more of these genes (MCDV-CP 1 , MCDV-CP 2  or MCDV-CP 3 ) is then incorporated in an expression cassette designed for suitable expression in a plant cell system. The resulting transformation vector is then introduced into maize to provide cross-protection to MCDV or related viral infections.

TECHNICAL FIELD

This invention relates to providing plants with resistance to maize chlorotic dwarf virus (MCDV) and viruses to which MCDV infection or resistance provides cross-resistance, including maize dwarf mosaic virus strain A (MDMV-A).

BACKGROUND OF THE INVENTION

Virus-induced diseases in agronomically important crops have cost farmers a great loss of income due to reduced yields. Traditionally, virus diseases have been controlled by breeding for host plant resistance or by controlling insects that transmit diseases. Chemical means of protection are not generally possible for most viruses, and where possible are not generally practical. It has been known for many years that viral symptoms can be reduced in virus-infected plants by prior inoculation with a mild strain of the same virus, a phenomena known as cross-protection, as described by Sequeira, L., Trends in Biotechnology, 2, 25 (1984). Cross-protection is considered successful if the disease symptoms of the superinfecting (the more virulent) virus can be delayed or suppressed. There are several disadvantages to applying this type of cross-protection to the field situation:

1) application of the mild strain virus to entire fields is usually not practical,

2) the mild strain might undergo mutation to a more highly virulent strain,

3) the protecting strain might interact synergistically with a non-related virus causing a severe pathogenic infection,

4) a protecting virus in one crop may be a severe pathogen in another crop, and

5) a protective strain may cause a significant loss of yield in itself.

One proposed solution to these disadvantages has been to introduce a single viral gene into the host plant genome to cross-protect, rather than infect with an intact virus. This single gene cross-protection strategy has already been proven successful using the coat protein gene from tobacco mosaic virus (TMV-CP). As reported by Abel, P. P., et. al., Science, 232, 738 (1986), transgenic tobacco plants, expressing TMV mRNA and coat protein (CP), demonstrated delayed or suppressed symptom development upon infection with TMV. TMV-CP transgenic tomato plants have been described by Nelson, R. S., et. al., Bio/Technology, 6, 403 (1988), to show evidence of protection from TMV as well as three strains of tomato mosaic virus (ToMV). Other approaches using DNA clones of viruses to engineer resistance include positive interference, as described by Golemboski et al. Proc. Natl. Acad. Sci. USA, 87, 6311 (1990) and Carr and Zaitlin, Mol. Pl. Microbe Inter., 4, 579 (1991); and antisense RNA, as described by Powell et al., Proc. Natl. Acad. Sci. USA, 86, 6949 (1989).

Numerous viruses exist for which resistance is desired. Maize chlorotic dwarf virus causes a somewhat variable mosaic or yellow streaking and occasional stunting in maize. Early infections can result in severe symptoms including premature death. The virus is spread by the blackfaced leafhopper (Graminella nigrifons). MCDV can overwinter in Johnsongrass (Sorghum halepense) and as a result has become a recurrent problem in areas where Johnsongrass is a common weed. Combined infections with maize dwarf mosaic virus can cause more severe symptoms although the syndrome is less well characterized than Corn Lethal Necrosis. Only limited success has been obtained to date in developing MCDV-resistant maize lines, due to the difficulties of selecting effidently for resistance to an obligately insect transmitted virus, as well as a lack of usable sources of resistance in agronomically useful maize lines. Thus, there is a continuing need for genes, plant transformation vectors, and transformed plant materials providing resistances to pathogenic viruses such as MCDV.

Unfortunately, while certain plant viruses, such as tobacco mosaic virus, have coat protein genes that are found on subgenomic RNA and are therefore relatively easy to identify and clone for use in engineered cross-protection, maize chlorotic dwarf virus belongs to a completely separate group, the only other (tentatively assigned) member of which is the spherical virus of the rice tungro disease (RTSV). In addition, MCDV has a number of unusual biological properties which make identification of an appropriate gene difficult. For example, all attempts to mechanically transmit MCDV have been unsuccessful. As another example, MCDV appears to be a phloem-restricted virus. MCDV also has three coat proteins, and it was not known whether expression of one protein would be sufficient to confer immunity or whether all three would need to be expressed. Nor was it known which protein would be the appropriate one to express if only one could be expressed. Further, the genome of MCDV has an unusual genome organization to provide for the expression of multiple coat proteins.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a schematic illustration of the manner in which the nucleic acid sequence of MCDV-type strain was obtained by sequencing overlapping cDNA clones.

FIG. 2 is an a schematic illustration of the unusual organization of the MCDV genome.

DISCLOSURE OF THE INVENTION

In the present invention, methods and materials are provided to isolate any or all of the three coat protein genes from maize chlorotic dwarf virus (MCDV). One or more of these genes (MCDV-CP_(x), where x is 1, 2, or 3) is then incorporated in an expression cassette designed for suitable expression in a plant cell system. The resulting transformation vector is then introduced into maize callus to provide cross-protection to MCDV-related viral infections. MCDV has a single, long RNA core having the sequence shown in SEQUENCE I.D. No. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides cDNA clones from the RNA genome of maize chlorotic dwarf virus which code substantially solely for the coat protein of the virus. These clones are incorporated into an expression cassette in which the cDNA clone is operably linked to plant or bacterial regulatory sequences which cause the expression of the cDNA clone in living plant or bacterial cells, respectively. It is important that the cloned gene have a start codon in the correct reading frame for the structural sequence. The resulting bacterial vectors can be readily inserted into bacteria for expression and characterization of the sequence. Accordingly, the present invention also provides bacterial cells containing as a foreign plasmid at least one copy of the foregoing bacterial expression cassette. In addition, the plant expression cassette preferably includes a strong constitutive promoter sequence at one end to cause the gene to be transcribed at a high level and a poly-A recognition sequence at the other end for proper processing and transport of the messenger RNA. An example of such a preferred (empty) expression cassette into which the cDNA of the present invention can be inserted is the pPHI414 plasmid developed by Beach et al. of Pioneer Hi-Bred International, Inc., Johnston, Iowa, as disclosed in U.S. patent application Ser. No. 07/785,648, filed Oct. 31, 1991. Highly preferred plant expression cassettes will be designed to include one or more selectable marker genes, such as kanamycin resistance or herbicide tolerance genes. The plant expression vectors of this invention can be inserted, using any convenient technique, including electroporation (in protoplasts), microprojectile bombardment, and microinjection, into cells from monocotyledonous or dicotyledonous plants, in cell or tissue culture, to provide transformed plant cells containing as foreign DNA at least one copy of the DNA sequence of the plant expression cassette. Preferably, the monocotyledonous species will be selected from maize, sorghum, wheat and rice, and the dicotyledonous species will be selected from soybean, alfalfa, tobacco and tomato. Using known techniques, protoplasts can be regenerated and cell or tissue culture can be regenerated to form whole fertile plants which carry and express the desired cDNA clone for MCDV coat protein. Accordingly, a highly preferred embodiment of the present invention is a transformed maize plant, the cells of which contain as foreign DNA at least one copy of the DNA sequence of an expression cassette of this invention.

Finally, this invention provides methods of imparting resistance to maize chlorotic dwarf virus to plants of a MCDV susceptible taxon, comprising the steps of:

a) culturing cells or tissues from at least one plant from the taxon,

b) introducing into the cells of the cell culture or tissue culture at least one copy of an expression cassette comprising a cDNA clone from the RNA genome of MCDV which codes substantially solely for the coat protein of the virus, operably linked to plant regulatory sequences which cause the expression of the cDNA clone in the cells, and

c) regenerating MCDV-resistant whole plants from the cell or tissue culture. Once whole plants have been obtained, they can be sexually or clonally reproduced in such manner that at least one copy of the sequence provided by the expression cassette is present in the cells of progeny of the reproduction.

Alternatively, once a single transformed plant has been obtained by the foregoing recombinant DNA method, conventional plant breeding methods can be used to transfer the coat protein gene and associated regulatory sequence via crossing and backcrossing. Such intermediate methods will comprise the further steps of

a) sexually crossing the MCDV resistant plant with a plant from the MCDV susceptible-taxon;

b) recovering reproductive material from the progeny of the cross; and

c) growing resistant plants from the reproductive material. Where desirable or necessary, the characteristics of the susceptible taxon can be substantially preserved by expanding this method to include the further steps of repetitively:

a) backcrossing the MCDV resistant progeny with MCDV susceptible plants from the susceptible taxon; and

b) selecting for expression of MCDV resistance among the progeny of the backcross,

until the desired percentage of the characteristics of the susceptible taxon are present in the progeny along with the gene imparting MCDV resistance.

By the term "taxon" herein is meant a unit of botanical classification of genus or lower. It thus includes genus, species, cultivars, varieties, variants, and other minor taxonomic groups which lack a consistent nomenclature.

It will also be appreciated by those of ordinary skill that the plant vectors provided herein can be incorporated into Agrobacterium tumefaciens or Agrobacterium rhizogenes, which can then be used to transfer the vector into susceptible plant cells, primarily from dicotyledonous species. Thus, this invention provides a method for imparting MCDV resistance in Agrobacterium-susceptible dicotyledonous plants in which the expression cassette is introduced into the cells by infecting the cells with Agrobacterium tumefaciens, a plasmid of which has been modified to include the plant expression cassette of this invention. The following description further exemplifies the compositions of this invention and the methods of making and using them. However, it will be understood that other methods, known by those of ordinary skill in the art to be equivalent, can also be employed.

1. Isolation and cloning of MCDV cDNA

The type strain of MCDV was maintained in the maize inbred Oh28 by transmission with the leafhopper G. nigrifrons and viral particles were isolated as previously described (Hunt et al., Phytopathology 78, 449 (1988)). MCDV particles were suspended in NETS (10 mM Tris, pH 7.5; 100 mM NaCl; 1 mM Na₂ EDTA; 0.5% SDS) and extracted with 1:1 chloroform:phenol to isolate MCDV RNA.

First and second strand cDNA synthesis were by the method of Gubler and Hoffman, Gene 25, 263 (1983) utilizing cDNA synthesis kits (Amersham, Arlington Heights, Ill.). For the initial cDNA libraries, double-stranded cDNA was treated with EcoRI methylase, ligated to GGAATTCC EcoRI linkers, digested with EcoRI and separated from linkers by column fractionation. The cDNA was ligated to EcoRI-cleaved ₋₋ gt10 and EcORI-cleaved, phosphatased (CIP) ₋₋ gt11 phage arms. After packaging, the ₋₋ gt10 phage were plated on bacterial strain NM514 and screened for MCDV-specific inserts by filter plaque hybridization (Benton and Davis, Science 196, 180 (1977)), using ³² P-labeled cDNA's random-primed from the MCDV genomic RNA. MCDV-positive phage were purified and the cDNA inserts subcloned into pUC119 (Vieira and Messing, Meth. Enzymol. 153, 3 (1987)) for further analysis. Hybridization positive clones from the initial gt10 library included: p3-13, p36-45, pH9, pK1, pG1, pC5 (FIG. 1). After packaging, the ₋₋ gt11 phage were plated on bacterial strain Y1090^(r-) and screened with antisera to either intact MCDV virions or isolated, individual MCDV capsid proteins (Maroon, MS Thesis, Ohio State University (1989)) as described by Mierendorf, et al. Meth. Enzymol. 152,458 (1987). Positive phage clones were identified with antisera specific to either cp1 or cp2, and cDNA inserts from these phage were subcloned into pUC119. The anti-cp1-specific cDNA clone, p7C5, and the anti-cp2-specific cDNA clones, p7E6 and p7D7, (FIG. 1) were chosen for study. Analysis of initial cDNAs revealed that a number of clones terminated at identical EcoRI sites which were shown to be present in the viral sequence. This result indicated that the methylation of the initial cDNAs was incomplete. To obtain cDNAs to the rest of MCDV and to overlap the initial clones, two additional cDNA libraries were prepared, one primed with oligo-dT(12-18) and one random-primed. Double-stranded cDNA prepared as above was ligated to a 20/24 nt. blunt end/EcoRI adaptor (Amersham), and adaptor cDNAs were kinased and ligated to EcoRI-cleaved/phosphatased pUC119. Plasmid clone pdT2 (FIG. 1) was derived from the dT-primed library and plasmids pL142, pL221, and pL411 (FIG. 1) were derived from the random-primed library.

2. Sequencing of MCDV cDNA

Single-stranded DNA templates for sequencing were derived by superinfection with M13K07 of bacterial strain MV1190 containing the pUC119 based cDNAs (FIG. 1), cloned in both orientations, as described by McMullen et al., Nuc. Acids Res., 14, 4953 (1986) and Vieira and Messing, Meth. Enzymol. 153, 3 (1987). Ordered deletions from the full-length single-stranded templates were prepared by the method of Dale et al., Plasmid 13, 31 (1985). Dideoxynudeotide sequencing reactions with the Klenow fragment of Pol. I or Sequenase (U.S. Biochemicals, Cleveland, Ohio) were performed using ³⁵ S-dATP. Greater than 99% of the total sequence was obtained from both strands and the majority was read from three or more templates. The 5' sequence not contained on cDNA was obtained by direct RNA sequencing, using the sequencing primer 5'-GGTCTACTCACGGCACGCCA-3' (SEQUENCE I.D. NO. 3) with an RNA sequencing kit (Boehringer Mannheim, Indianapolis, Ind.) as recommended except that tailing of reaction products with dTTP by terminal deoxynucleotidyl transferase using the method of DeBorde et al., Anal. Biochem. 157,275 (1986) was added to improve resolution of final bases.

To obtain the amino-terminal protein sequence of MCDV capsid proteins, MCDV particles were disrupted in Laemmli loading buffer and the individual capsid protein separated on a 12.5%-4% Laemmli slab gel (Laemmli, Nature 227, 680 (1970)). The proteins were electrotransfered to Immobilon-P membrane (Millipore, Bedford, Mass.) using a 10 mM CAPS, pH 11.0; 10% MeOH transfer buffer, stained with Coomassie Blue R-250 for visualization and excised. Automated amino-terminal protein sequencing was performed by the Iowa State University Biochemistry Instrumentation Center (Ames, Iowa).

DNA and protein sequence analysis was performed using the IntelliGenetics (Mountain View, Calif.) molecular biology software on a Digital VAX 8250 located at the USDA-ARS-ASRR (Agricultural Systems Research Resource) Beltsville, Md.

The nucleic acid sequence of MCDV-type strain was obtained by sequencing overlapping cDNA clones (FIG. 1) that covered all but 13 nucleotides at the 5' terminus of MCDV. The 5' end sequence was obtained by direct RNA sequencing. Despite repeated attempts and the use of terminal transferase in the manner of DeBorde et al., Anal. Biochem., 157, 275 (1986) the first nucleotide could not be definitely determined. In part for this reason, the expressions "coding substantially for" and "coding substantially solely for" are used herein, and with regard to the use of the word "substantially" refer to sequences which code for no more than a few (five or less) amino acids greater or lesser on either end of the desired protein or proteins, or which have an equivalent number of nucleotide bases more or less than the native sequence.

The genomic RNA of MCDV-type (SEQUENCE I.D. NO. 4) was determined to be 11785 nucleotides long, exclusive of the poly-A tail at the 3' terminus. This sequence permits the construction of a DNA molecule which codes for the entire maize chlorotic dwarf virus, or any portion or functional unit thereof which is useful in conferring resistance to the virus when expressed in plant cells. Such resistance can readily be evaluated using routine testing methods such as those disclosed herein. Computer analysis of the sequence indicated a long open reading frame from nucleotide 456 to nucleotide 10826. The translation of this open reading frame would result in a protein of 3457 and no acids with a derived molecular weight of 388,890 daltons. The open reading frame begins with two AUG triplets, neither of which is in a particularly favorable context for initiation of translation when compared with the analyses of translation start sequences by Lutcke et al., EMBO J. 6, 43 (1987); and Kosak, J. Cell Biol. 108, 229 (1989) by the scanning model. In addition, there are 13 AUG triplets preceding the double AUG that starts the open reading frame. A long untranslated 3' leader containing multiple AUG triplets before the beginning of a very long reading frame is similar to the animal picornaviruses as described by Stanway, J. Gen. Virol. 71, 2483 (1990). Internal initiation at the AUG for the long open reading frame has been demonstrated to occur for a number of the animal picornaviruses as seen in Pelletier and Sonenberg, Nature, 334, 320 (1988) and Jang et al., J. Virol., 63, 1651 (1989). The mechanism for initiation of translation for MCDV has not been characterized.

The derived amino acid sequence of MCDV-type was compared to the Protein Identification Resource, Version 32 and the University of Geneva, Version 22, protein data banks for sequence similarity using the IFIND (IntelliGenetics) program based on the algorithm of Wilber and Lipman, Proc. Natl. Acad. Sci. USA, 80, 726 (1983). The highest similarity score was with the comovirus, cowpea mosaic virus (CPMV) as reported by Lomonossoff and Shanks, EMBO J., 2, 2253 (1983) and the second highest score was with the nepovirus, grapevine fanleaf virus (GFLV) as reported by Ritzenthaler et al., J. Gen. Virol., 72, 2357 (1991). For both viruses the region of similarity preceded and included the first conserved motif of RNA-dependent RNA polymerases as defined by Poch et al. EMBO J., 8, 3867 (1989). The IFIND program identified weaker similarity with additional nepoviruses and some of the animal picornaviruses. The conservation of protein sequence and gene order for the plant comoviruses, nepoviruses and potyviruses, and the animal picornaviruses is well documented by, inter alia, Agros et al., Nuc. Acids Res., 12, 7251 (1984); Goldbach, Ann. Rev. Phytopath., 24, 289 (1986); and Domier et al., Virology, 158, 20 (1987) and has led to the proposal of the picornavirus-like "supergroup". Two additional conserved protein regions involved in genome replication for picorna-like viruses are the NTP binding/helicase region, as described by Agros et al., above, and Gorbalenya et al., Nuc. Acids Res., 17, 4713 (1989) and the C-terminal region, cysteine active site of the 3C-like proteases, as also described by Agros et al., above, and by Grief et al., J. Gen. Virol., 69, 1517 (1988).

The electrophoresis of MCDV virions on denaturing protein gels reveals three structural proteins, designated cp1, cp2 and cp3 with molecular weights of 32.5 kd, 27 kd, and 24.5 kd; respectively. Antiserum specific to cp1 was used to screen a ₋₋ gt11 library to isolate the clone p7C5, and antiserum specific to cp2 was used to identify the cDNAs p7E6 and p7D7 (FIG. 1). This result indicated that an antigenic region of cp1 was located between 4063-4903 and an antigenic region of cp2 was located between 1815-2941. Automated amino-terminal sequencing was performed on each of the MCDV capsid proteins. The amino-terminus of cp2 was apparently blocked as no sequence was obtained. The 15 amino acids at the NH₂ -terminus of cp3 were determined to be LQVASLTDIGELSSV, as shown in SEQUENCE I.D. NO. 2 and SEQUENCE I.D. NO. 6. This sequence is an exact match to the derived protein sequence encoded by nucleotides 3144-3188. Likewise, the 15 amino acids at the NH₂ -terminus of cp1, VSLGRSFENGVLIGS, as shown in SEQUENCE I.D. NO. 5 and SEQUENCE I.D. NO. 7, are an exact match to the derived protein sequence encoded by nucleotides 3750-3794. Both proteins must be derived by proteolytic cleavage of the large polyprotein. The Gln/Leu cleavage at the NH₂ -terminus of cp3 and Gln/Val cleavage at the NH₂ -terminus of cp1 are dipeptide cleavage sites that may be used by animal picornavirus 3C proteases, according to Krausslich and Wimmer, Ann. Rev. Biochem., 57, 754 (1988), which could indicate that the 3C-similar region of the MCDV may function in capsid protein processing. Assuming that cp3 begins with the Leu at the Gln/Leu cleavage and ends with the GIn at the Gln/Val cleavage for cp1, cp3 would have a derived MW of 21,933, a little less than the 24.5 kd MW determined by SDS gel electrophoresis. Although protein sequence was not obtained for cp2, the position of clones p7E6 and p7D7, and the finding that protein fusions expressed from the pEX vector for the PstI fragments 2076-2619 and 2613-3149 reacted positively with cp2-specific antiserum (McMullen, unpublished), is consistent with cp2 preceding cp3 in the polyprotein similar to the order of vp2-vp3-vp1 for the animal picornaviruses. However, it is still not known if the coding region for cp2 immediately precedes cp3.

The overall genome structure of MCDV-type strain is shown in FIG. 2. MCDV genome organization resembled that of the animal picornaviruses, a single large polyprotein in which the capsid proteins are encoded 5' of the proteins presumed to be involved in genome replication. Depending on the exact location of cp2, the MCDV genome can encode up to 78 kd of protein 5' of the capsid proteins for which there are no corresponding animal picornavirus protein. This region may encode plant virus specific functions such as cell-to-cell movement or helper protein for insect transmission. Because MCDV is a phloem restricted virus, there is no evidence for a virus-encoded cell-to-cell movement protein. However, there is evidence for the presence of an insect transmission helper component in MCDV-infected plants according to Hunt et al., Phytopathology, 78, 449 (1988). The presence of plant-virus-specific proteins at the NH² -terminus of the polyprotein would allow addition of these proteins without disruption of the cp proteins-replication functions genome structure typical of picornaviruses.

3. Design of the plasmid vector.

The gene MCDV coat protein 3 was placed under control of tandem cauliflower mosaic virus 35S promoters isolated from the 1841 strain of the virus, and a polyadenylation signal sequence obtained from the potato proteinase inhibitor II (Pin II) gene that exhibits enhancer-like activity. The chimeric gene also included a 79 bp sequence Ω' from the 5' leader region of tobacco mosaic virus (TMV) that functions as a translational enhancer; and a Zea mays alcohol dehydrogenase 1, intron 1 fragment (ADH) spanning nucleotides 119-672, trimmed to 557 bp with Bal 31 nuclease, which has been shown to function as an enhancer of gene expression in monocots. The plasmids were grown in E. coli and purified by the known polyethylene glycol precipitation method of Sambrook et al., Molecular Cloning, 1, 40 (1989). Purity was confirmed by electrophoretic analysis of the DNA fragments obtained after digestion with restriction endonucleases. The plasmid was designated pPHI1406 and the sequence is shown in SEQUENCE I.D. No. 1.

4. Preparation of the recipient organism.

Separately, an embryogenic cell suspension line 54-68-5 was established from immature embryos obtained from a cross between a line derived from the public inbred corn line B73 and a WX 1-9 translocation stock of public inbred corn line W23.

5. Transformation

Suspension cells from (4) were bombarded with 1 μl aliquots of a 30 μl mixture containing 10 μg of purified plasmid DNA (5 μg of the MCDV plasmid pPHI1406 (SEQUENCE I.D. No. 1), and 5 μg of the same plasmid in which the BAR (Basta resistance) gene was substituted for the MCDV cp3 gene) precipitated onto 1 μm tungsten particles as described by numerous articles including Klein, T. M., et al., 1988 (May) Bio/Technology 6:559-563; Klein, T. M., et al., 1988 (June) Proc. Natl. Acad. Sci. U.S.A. 85:4305-4309; T. M. Klein, et al., "Stable Genetic Transformation of Intact Applicant Nicotiana Cells by the Particle Bombardment Process", Proc. Natl. Acad. Sci. USA, Vol. 85, November 1988, pp. 8502-8505; D. T. Tomes, et al., "Transgenic Tobacco Plants and their Progeny Derived by Microprojectile Bombardment of Tobacco Leaves", Plant Molecular Biology, Vol. 14, No. 2, February, 1990, pp. 261-268, Kluwer Academic Publishers, BE; and M. C. Ross, et al., "Transient and Stable Transgenic Cells and Calli of Tobacco and Maize Following Microprojectile Bombardment", J. Cell. Biochem., Suppl. 13D, 27th Mar.-April 1989, P. 268, Abstract No. M. 149, Alan R. Liss, Inc. New York, U.S.; and plated onto selective medium containing 5 ppb phosphinothricin (Basta™).

Following a prolonged period of selection and callus growth, regeneration was initiated by placing callus on a Murashige & Skoog medium modified by addition of 0.5 mg/12,4-D and 5 ppb Basta. Embryogenic callus was selected and transferred to medium lacking 2,4-D and kept in a lighted growth room. Germinated plantlets were placed in culture tubes and finally planted out into soil in pots in the greenhouse.

More than 150 R₀ (recombinant) plants were obtained, representing twenty independent transformation events. Transformation was confirmed by PCR amplification of a DNA fragment spanning part of the MCDV coat protein gene and the CaMV promoter. Genomic DNA samples, in which a fragment of the expected size was successfully amplified were presumed to be transformed. These plants were pollinated with pollen from non-transgenic B73 plants and the resulting R₁ seed was planted in a field trial under USDA supervision. The resulting plants exhibited a virus resistant phenotype, i.e., they survived and set seed under virus infection conditions in which non-transgenic plants died prematurely, as seen in the following table:

    ______________________________________                                         Field Test Results                                                                              Transgenic                                                                             Control                                               ______________________________________                                         Number of Plants   379       32                                                Number of Harvestable Ears                                                                         52        0                                                % Harvested vs. Total                                                                             13.7%       0%                                              ______________________________________                                    

The screening was performed in a manner to insure maximum infection levels and severity. Thus, the level of resistance seen in this extreme test corresponds to effective, usable virus tolerance when the transformants of this invention are used trader normal farming conditions.

The MCDV resistance is a simply inherited, dominant trait and can, if desired, be introduced into other maize varieties by simple crossing or backcrossing. In addition to providing resistance to MCDV, this invention is also capable of conferring resistance to viruses to which plants obtain cross-resistance through infection by MCDV. In the field test described above, resistance to maize dwarf mosaic virus strain A (MDMV-A) was also observed. Accordingly, this invention provides resistance to that virus as well.

    __________________________________________________________________________     SEQUENCE LISTING                                                               (1) GENERAL INFORMATION:                                                       (iii) NUMBER OF SEQUENCES: 7                                                   (2) INFORMATION FOR SEQ ID NO: 1:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5033 base pairs                                                    (B) TYPE: nucleotide                                                           (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: synthetic DNA                                              (A) DESCRIPTION: transformation plasmid pPHI1406                               (iii) HYPOTHETICAL: No                                                         (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 1:                                       TCGCGCGTTTCGGTGATGACGGTGAAAACCTCTGACACATGCAGCTCCCG50                           GAGACGGTCACAGCTTGTCTGTAAGCGGATGCCGGGAGCAGACAAGCCCG100                          TCAGGGCGCGTCAGCGGGTGTTGGCGGGTGTCGGGGCTGGCTTAACTATG150                          CGGCATCAGAGCAGATTGTACTGAGAGTGCACCATATGCGGTGTGAAATA200                          CCGCACAGATGCGTAAGGAGAAAATACCGCATCAGGCGCCATTCGCCATT250                          CAGGCTGCGCAACTGTTGGGAAGGGCGATCGGTGCGGGCCTCTTCGCTAT300                          TACGCCAGCTGGCGAAAGGGGGATGTGCTGCAAGGCGATTAAGTTGGGTA350                          ACGCCAGGGTTTTCCCAGTCACGACGTTGTAAAACGACGGCCAGTGCCAA400                          GCTCAGATCTGAGCTTCTAGAAATCCGTCAACATGGTGGAGCACGACACT450                          CTCGTCTACTCCAAGAATATCAAAGATACAGTCTCAGAAGACCAAAGGGC500                          TATTGAGACTTTTCAACAAAGGGTAATATCGGGAAACCTCCTCGGATTCC550                          ATTGCCCAGCTATCTGTCACTTCATCAAAAGGACAGTAGAAAAGGAAGGT600                          GGCACCTACAAATGCCATCATTGCGATAAAGGAAAGGCTATCGTTCAAGA650                          TGCCTCTGCCGACAGTGGTCCCAAAGATGGACCCCCACCCACGAGGAGCA700                          TCGTGGAAAAAGAAGACGTTCCAACCACGTCTTCAAAGCAAGTGGATTGA750                          TGTGATGCTCTAGAAATCCGTCAACATGGTGGAGCACGACACTCTCGTCT800                          ACTCCAAGAATATCAAAGATACAGTCTCAGAAGACCAAAGGGCTATTGAG850                          ACTTTTCAACAAAGGGTAATATCGGGAAACCTCCTCGGATTCCATTGCCC900                          AGCTATCTGTCACTTCATCAAAAGGACAGTAGAAAAGGAAGGTGGCACCT950                          ACAAATGCCATCATTGCGATAAAGGAAAGGCTATCGTTCAAGATGCCTCT1000                         GCCGACAGTGGTCCCAAAGATGGACCCCCACCCACGAGGAGCATCGTGGA1050                         AAAAGAAGACGTTCCAACCACGTCTTCAAAGCAAGTGGATTGATGTGATA1100                         TCTCCACTGACGTAAGGGATGACGCACAATCCCACTATCCTTCGCAAGAC1150                         CCTTCCTCTATATAAGGAAGTTCATTTCATTTGGAGAGGACGAGCTGCAG1200                         CTTATTTTTACAACAATTACCAACAACAACAAACAACAAACAACATTACA1250                         ATTACTATTTACAATTACAGTCGACGGATCAAGTGCAAAGGTCCGCCTTG1300                         TTTCTCCTCTGTCTCTTGATCTGACTAATCTTGGTTTATGATTCGTTGAG1350                         TAATTTTGGGGAAAGCTTCGTCCACAGTTTTTTTTTCGATGAACAGTGCC1400                         GCAGTGGCGCTGATCTTGTATGCTATCCTGCAATCGTGGTGAACTTATGT1450                         CTTTTATATCCTTCACTACCATGAAAAGACTAGTAATCTTTCTCGATGTA1500                         ACATCGTCCAGCACTGCTATTACCGTGTGGTCCATCCGACAGTCTGGCTG1550                         AACACATCATACGATATTGAGCAAAGATCGATCTATCTTCCCTGTTCTTT1600                         AATGAAAGACGTCATTTTCATCAGTATGATCTAAGAATGTTGCAACTTGC1650                         AAGGAGGCGTTTCTTTCTTTGAATTTAACTAACTCGTTGAGTGGCCCTGT1700                         TTCTCGGACGTAAGGCCTTTGCTGCTCCACACATGTCCATTCGAATTTTA1750                         CCGTGTTTAGCAAGGGCGAAAAGTTTGCATCTTGATGATTTAGCTTGACT1800                         ATGCGATTGCTTTCCTGGACCCGTGCAGCTGCGGACGGATCCACCATGGC1850                         ACTGCAGGTGGCATCTCTTACAGACATAGGAGAATTGAGCAGTGTGGTTG1900                         CTACTGGTTCTTGGTCTACTACCTCGGCTACTAATTTGATGGAATTAAAC1950                         ATTCATCCCACCTCCTGTGCTATTCAGAACGGATTGATAACACAGACACC2000                         ATTGAGTGTTTTAGCTCATGCTTTTGCAAGGTGGAGAGGATCGTTGAAAA2050                         TTTCCATCATTTTCGGAGCGAGTTTGTTTACCCGAGGACGAATCTTAGCC2100                         GCTGCTGTGCCCGTTGCTAAGCGCAAAGGTACCATGAGCCTTGACGAGAT2150                         TAGTGGGTATCATAATGTTTGCTGCTTATTGAATGGTCAGCAAACTACAT2200                         TTGAATTGGAAATCCCATATTATTCTGTGGGCCAAGATTCTTTCGTGTAC2250                         CGTGATGCTCTTTTTGATATCTCTGCGCACGATGGGAATTTTATGATTAC2300                         TCGCTTGCATCTCGTGATACTGGATAAATTGGTAATGAGCGCTAATGCGA2350                         GCAACAGCATAAATTTTTCCGTGACTCTTGGACCAGGTTCTGATTTGGAA2400                         TTGAAATATCTTGCAGGAGTACATGGGCAGCGCATAGTCCGCGAGTTGAA2450                         GATGCAGTGATCAACCTAGACTTGTCCATCTTCTGGATTGGCCAACTTAA2500                         TTAATGTATGAAATAAAAGGATGCACACATAGTGACATGCTAATCACTAT2550                         AATGTGGGCATCAAAGTTGTGTGTTATGTGTAATTACTAGTTATCTGAAT2600                         AAAAGAGAAAGAGATCATCCATATTTCTTATCCTAAATGAATGTCACGTG2650                         TCTTTATAATTCTTTGATGAACCAGATGCATTTCATTAACCAAATCCATA2700                         TACATATAAATATTAATCATATATAATTAATATCAATTGGGTTAGCAAAA2750                         CAAATCTAGTCTAGGTGTGTTTTGCGAATTGCGGCCGCGATCTGGGGAAT2800                         TCGTAATCATGGTCATAGCTGTTTCCTGTGTGAAATTGTTATCCGCTCAC2850                         AATTCCACACAACATACGAGCCGGAAGCATAAAGTGTAAAGCCTGGGGTG2900                         CCTAATGAGTGAGCTAACTCACATTAATTGCGTTGCGCTCACTGCCCGCT2950                         TTCCAGTCGGGAAACCTGTCGTGCCAGCTGCATTAATGAATCGGCCAACG3000                         CGCGGGGAGAGGCGGTTTGCGTATTGGGCGCTCTTCCGCTTCCTCGCTCA3050                         CTGACTCGCTGCGCTCGGTCGTTCGGCTGCGGCGAGCGGTATCAGCTCAC3100                         TCAAAGGCGGTAATACGGTTATCCACAGAATCAGGGGATAACGCAGGAAA3150                         GAACATGTGAGCAAAAGGCCAGCAAAAGGCCAGGAACCGTAAAAAGGCCG3200                         CGTTGCTGGCGTTTTTCCATAGGCTCCGCCCCCCTGACGAGCATCACAAA3250                         AATCGACGCTCAAGTCAGAGGTGGCGAAACCCGACAGGACTATAAAGATA3300                         CCAGGCGTTTCCCCCTGGAAGCTCCCTCGTGCGCTCTCCTGTTCCGACCC3350                         TGCCGCTTACCGGATACCTGTCCGCCTTTCTCCCTTCGGGAAGCGTGGCG3400                         CTTTCTCATAGCTCACGCTGTAGGTATCTCAGTTCGGTGTAGGTCGTTCG3450                         CTCCAAGCTGGGCTGTGTGCACGAACCCCCCGTTCAGCCCGACCGCTGCG3500                         CCTTATCCGGTAACTATCGTCTTGAGTCCAACCCGGTAAGACACGACTTA3550                         TCGCCACTGGCAGCAGCCACTGGTAACAGGATTAGCAGAGCGAGGTATGT3600                         AGGCGGTGCTACAGAGTTCTTGAAGTGGTGGCCTAACTACGGCTACACTA3650                         GAAGGACAGTATTTGGTATCTGCGCTCTGCTGAAGCCAGTTACCTTCGGA3700                         AAAAGAGTTGGTAGCTCTTGATCCGGCAAACAAACCACCGCTGGTAGCGG3750                         TGGTTTTTTTGTTTGCAAGCAGCAGATTACGCGCAGAAAAAAAGGATCTC3800                         AAGAAGATCCTTTGATCTTTTCTACGGGGTCTGACGCTCAGTGGAACGAA3850                         AACTCACGTTAAGGGATTTTGGTCATGAGATTATCAAAAAGGATCTTCAC3900                         CTAGATCCTTTTAAATTAAAAATGAAGTTTTAAATCAATCTAAAGTATAT3950                         ATGAGTAAACTTGGTCTGACAGTTACCAATGCTTAATCAGTGAGGCACCT4000                         ATCTCAGCGATCTGTCTATTTCGTTCATCCATAGTTGCCTGACTCCCCGT4050                         CGTGTAGATAACTACGATACGGGAGGGCTTACCATCTGGCCCCAGTGCTG4100                         CAATGATACCGCGAGACCCACGCTCACCGGCTCCAGATTTATCAGCAATA4150                         AACCAGCCAGCCGGAAGGGCCGAGCGCAGAAGTGGTCCTGCAACTTTATC4200                         CGCCTCCATCCAGTCTATTAATTGTTGCCGGGAAGCTAGAGTAAGTAGTT4250                         CGCCAGTTAATAGTTTGCGCAACGTTGTTGCCATTGCTACAGGCATCGTG4300                         GTGTCACGCTCGTCGTTTGGTATGGCTTCATTCAGCTCCGGTTCCCAACG4350                         ATCAAGGCGAGTTACATGATCCCCCATGTTGTGCAAAAAAGCGGTTAGCT4400                         CCTTCGGTCCTCCGATCGTTGTCAGAAGTAAGTTGGCCGCAGTGTTATCA4450                         CTCATGGTTATGGCAGCACTGCATAATTCTCTTACTGTCATGCCATCCGT4500                         AAGATGCTTTTCTGTGACTGGTGAGTACTCAACCAAGTCATTCTGAGAAT4550                         AGTGTATGCGGCGACCGAGTTGCTCTTGCCCGGCGTCAATACGGGATAAT4600                         ACCGCGCCACATAGCAGAACTTTAAAAGTGCTCATCATTGGAAAACGTTC4650                         TTCGGGGCGAAAACTCTCAAGGATCTTACCGCTGTTGAGATCCAGTTCGA4700                         TGTAACCCACTCGTGCACCCAACTGATCTTCAGCATCTTTTACTTTCACC4750                         AGCGTTTCTGGGTGAGCAAAAACAGGAAGGCAAAATGCCGCAAAAAAGGG4800                         AATAAGGGCGACACGGAAATGTTGAATACTCATACTCTTCCTTTTTCAAT4850                         ATTATTGAAGCATTTATCAGGGTTATTGTCTCATGAGCGGATACATATTT4900                         GAATGTATTTAGAAAAATAAACAAATAGGGGTTCCGCGCACATTTCCCCG4950                         AAAAGTGCCACCTGACGTCTAAGAAACCATTATTATCATGACATTAACCT5000                         ATAAAAATAGGCGTATCACGAGGCCCTTTCGTC5033                                          (2) INFORMATION FOR SEQ ID NO: 2:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 45 bases                                                           (B) TYPE: nucleotide                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: viral RNA                                                  (A) DESCRIPTION: RNA codons for first 15 amino acids at 5'                     end of MCDV coat protein 3 (CP3)                                               (iii) HYPOTHETICAL: No                                                         (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2:                                       CUGCAGGUGGCAUCUCUUACAGACAUAGGAGAAUUGAGCAGUGUG45                                LeuGlnValAlaSerLeuThrAspIleGlyAspLeuSerSerVal                                  51015                                                                          (2) INFORMATION FOR SEQ ID NO: 3:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20 bases                                                           (B) TYPE: nucleotide                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: synthetic DNA                                              (A) DESCRIPTION: sequencing primer                                             (iii) HYPOTHETICAL: No                                                         (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 3:                                       GGTCTACTCACGGCACGCCA20                                                         (2) INFORMATION FOR SEQ ID NO: 4:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 11785 bases                                                        (B) TYPE: nucleotide                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: viral RNA                                                  (iii) HYPOTHETICAL: No                                                         (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4:                                       NUGAAAAGGAGGGUAUAGAGAUACCCUUCAUAUAUUCUGCGGAUGGCGUG50                           CCGUGAGUAGACCUCGCGACGUUUCCCAGAGGAAAAUGGAAAUGGUCCAU100                          GUAACACCAGAUAUUUAUCUGGUUGAGGAACAUGGUUUAGUGGUAGAGAU150                          AAACUCAACUUUGUGUUGGACCCCGAUGCUGUGAAAAGUAAAUAAAGACA200                          AGGCCACUUAGCGAAGGAUAUUCGAAGUAGUGAUGAAAGGAAGUGCAAUA250                          AGUCAUGCCGUAAGUCGCAAUGCGCUAUAAGUCAUGCCGUAAGCCGCGUC300                          GCCUGGAUUUGCUAUUAGAAUGUCCCUAGCCGGUGAUAACCUUGAGUCCC350                          CGUCAUAGGACUACUUUUGUUUGCUUAGUAAUACAUUGGGACCACCCGCA400                          UGGAGCUCUGAGCCUACCAUACAUAGUACAUUUUCCGAGGGAUUGUCUUU450                          UGAUAAUGAUGCAGACAAACAACAACCAAAAUCCC485                                         MetMetGlnThrAsnAsnAsnGlnAsnPro                                                 510                                                                            ACUCAAGGAAGCAUUCCUGAGAACUCCUCACAAGAUCGCAACUUA530                               ThrGlnGlySerIleProGluAsnSerSerGlnAspArgAsnLeu                                  152025                                                                         GGAGUGCCCGCUGGAUAUUCUUUAAGCGUUGAGGACCCCUUCGGG575                               GlyValProAlaGlyTyrSerLeuSerValGluAspProPheGly                                  303540                                                                         AACCGGUCUGACUUUCAUAUCCCAGUGCACCAAAUCAUUCGGGAA620                               AsnArgSerAspPheHisIleProValHisGlnIleIleArgGlu                                  455055                                                                         GAGAUUGAUCGUCCAAAUUGGGUUCCUAUAUGUUCAAACGAUUUU665                               GluIleAspArgProAsnTrpValProIleCysSerAsnAspPhe                                  606570                                                                         CAUCUUAACAGUGAGGAUUAUUGUGAGGAGUGCGAAUCUGAACGG710                               HisLeuAsnSerGluAspTyrCysGluGluCysAspSerAspArg                                  758085                                                                         AUCAAAAAUUUCGAAAUAUUCAGAUCACAGAAUUUGAUUGACCAA755                               IleLysAsnPheAspIlePheArgSerGlnAsnLeuIleAspGln                                  9095100                                                                        CACCUAAAUCUCUGUACUGAUUCAAAGGAUUGUGAUCAUUUUUCU800                               HisLeuAsnLeuCysThrAspSerLysAspCysAspHisPheSer                                  105110115                                                                      UGUUUUUCCACGAGUACAAGUUGCAGAUUUUGCCCUUUUUGCUUA845                               CysPheSerThrSerThrSerCysArgPheCysProPheCysLeu                                  120125130                                                                      UUCAUUUUUAAUUUGGAUAAAUUUUACAAACAAAAUCUAUAUUUG890                               PheIlePheAsnLeuAspLysPheTyrLysGlnAsnLeuTyrLeu                                  135140145                                                                      AUUAGUCGUCAGGCUCUAGCUAGAUUGUUCCACGGAAGCGCCGAA935                               IleSerArgGlnAlaLeuAlaArgLeuPheHisGlySerAlaAsp                                  150155160                                                                      GAGUUACUCAGUAGAGCGAUUUUCUUUACGUAUAAUAUUUGUAUU980                               GluLeuLeuSerArgAlaIlePhePheThrTyrAsnIleCysIle                                  165170175                                                                      GAUGCAGAGGUGGUUGCUAAUAAUAGGAUUGGCUGUGAAUAUGUU1025                              AspAlaGluValValAlaAsnAsnArgIleGlyCysAspTyrVal                                  180185190                                                                      AAGUUGUUUCAUCCAGACCUUAGGCCUAGUAUUACGUCUCCCCCU1070                              LysLeuPheHisProAspLeuArgProSerIleThrSerProPro                                  195200205                                                                      UAUGCUAGUGAUUGGGUUAUGUGUGAUAAUGCUAAACAUCUUUUU1115                              TyrAlaSerAspTrpValMetCysAspAsnAlaLysHisLeuPhe                                  210215220                                                                      GAGUGUCUUGGCCUUGGUGACACGACCAGAGGACACCUAUAUGGA1160                              GluCysLeuGlyLeuGlyAspThrThrArgGlyHisLeuTyrGly                                  225230235                                                                      CUUAUUAGCGAGAAUGCAUAUUGGAACGCCACGUGCUCAAAAUGC1205                              LeuIleSerGluAsnAlaTyrTrpAsnAlaThrCysSerLysCys                                  240245250                                                                      GGAGCCUGUUGUCAGGGAGCAAAUGCCCGUACGGCGAUACCGAUA1250                              GlyAlaCysCysGlnGlyAlaAsnAlaArgThrAlaIleProIle                                  255260265                                                                      GUGAUGGCGUUGCAGUACUGCAGGGUGGAUGUGUAUUAUAGUGAG1295                              ValMetAlaLeuGlnTyrCysArgValAspValTyrTyrSerGlu                                  270275280                                                                      UACUAUUUAUACCACAUCUACGCUCCGGAAGAGAGAAUGAAGAUU1340                              TyrTyrLeuTyrHisIleTyrAlaProAspGluArgMetLysIle                                  285290295                                                                      GAUCAACAGACAGCACACUUGCUACACAGUAUAAUCCGAGGAGCA1385                              AspGlnGlnThrAlaHisLeuLeuHisSerIleIleArgGlyAla                                  300305310                                                                      CCAGCAGUGGAUUGCUCUGAGUUAUCUCAGGAGCCAAUUCACAGG1430                              ProAlaValAspCysSerGluLeuSerGlnGluProIleHisArg                                  315320325                                                                      AUGGUAAUGGAUAGCUCAAAGUUAGUGGCACUGGAUUCGACAAUC1475                              MetValMetAspSerSerLysLeuValAlaLeuAspSerThrIle                                  330335340                                                                      AGGCAUCCUAAGAGCCAAGGAAGUUUGCUCGAUUCAGAAUGCGAU1520                              ArgHisProLysSerGlnGlySerLeuLeuAspSerAspCysAsp                                  345350355                                                                      CAUGAGUUUAUUCUAAGAACGUCCCAUGGUAUCAAAAUACCGAUG1565                              HisGluPheIleLeuArgThrSerHisGlyIleLysIleProMet                                  360365370                                                                      AGUAAGUCUUUAUUUAUAUCAUUUCUUACCAUGGGAGCUUAUCAU1610                              SerLysSerLeuPheIleSerPheLeuThrMetGlyAlaTyrHis                                  375400405                                                                      GGGUAUGCUCAUGAUGAUCAGCAGGAGCAAAAUGCGAUAAUAUCU1655                              GlyTyrAlaHisAspAspGlnGlnGluGlnAsnAlaIleIleSer                                  410415420                                                                      UUUGGUGGGAUGCCCGGAGUCAAUUUGGCUUGUAACAAAAAUUUC1700                              PheGlyGlyMetProGlyValAsnLeuAlaCysAsnLysAsnPhe                                  425430435                                                                      CUGAGAAUGCAUAAGUUGUUUUAUUCUGGAAGUUUUAGGCGCAGA1745                              LeuArgMetHisLysLeuPheTyrSerGlySerPheArgArgArg                                  440445450                                                                      CCCCUGUUUAUGAGCCAAAUUCCCUCUACGAAUGCCACCGCUCAG1790                              ProLeuPheMetSerGlnIleProSerThrAsnAlaThrAlaGln                                  455460465                                                                      UCCGGUUUUAAUGAUGAAGAAUUCGAAAGAUUGAUGGCUGAAGAG1835                              SerGlyPheAsnAspAspAspPheAspArgLeuMetAlaAspGlu                                  470475480                                                                      GGUGUGCAUGUCAAAGUCGAGCGUCCAAUAGCAGAGAGGUUUGAU1880                              GlyValHisValLysValGluArgProIleAlaGluArgPheAsp                                  485490500                                                                      UAUGAGGACGUUAUUGAUAUUUACGAUGAGACCGACCACGACAGG1925                              TyrGluAspValIleAspIleTyrAspGluThrAspHisAspArg                                  505510515                                                                      ACACGAGCUCUAGGCCUUGGCCAAGUAUUCGGAGGUUUGCUCAAA1970                              ThrArgAlaLeuGlyLeuGlyGlnValPheGlyGlyLeuLeuLys                                  520525530                                                                      GGAAUUUCUCAUUGUGUAGAUAGCCUACAUAAGGUAUUUGAUUUC2015                              GlyIleSerHisCysValAspSerLeuHisLysValPheAspPhe                                  535540545                                                                      CCUCUGGACCUGGCCAUAGAAGCAGCUCAGAAAACUGGUGAUUGG2060                              ProLeuAspLeuAlaIleAspAlaAlaGlnLysThrGlyAspTrp                                  550555560                                                                      CUUGAAGGAAAUAAAGCUGCAGUAGAUGAAACUAAAAUUUGUGUG2105                              LeuAspGlyAsnLysAlaAlaValAspAspThrLysIleCysVal                                  565670675                                                                      GGCUGUCCCGAGAUUCAAAAAGAUAUGAUCAGUUUCCAGAAUGAA2150                              GlyCysProGluIleGlnLysAspMetIleSerPheGlnAsnAsp                                  580585590                                                                      ACAAAAGAAGCUUUUGAAUUAAUACGAUCAAGUAUAAAGAAGCUU2195                              ThrLysAspAlaPheAspLeuIleArgSerSerIleLysLysLeu                                  595600605                                                                      UCCGAGGGCAUUGACAAAAUCACGAAGAUGAAUGCUACGAACUUU2240                              SerGluGlyIleAspLysIleThrLysMetAsnAlaThrAsnPhe                                  610615620                                                                      GAACGAAUCCUAGACGGGAUUAAACCAAUCGAGAGCAGGUUGACA2285                              AspArgIleLeuAspGlyIleLysProIleGluSerArgLeuThr                                  625630635                                                                      GAACUUGAGAACAAGGCACCCGCUUCAGACAGCAAAGCCAUGGAA2330                              AspLeuGluAsnLysAlaProAlaSerAspSerLysAlaMetAsp                                  640645650                                                                      GCUCUGGUCCAGGCCGUGAAAGACUUGAAAAUCAUGAAAGAGGCG2375                              AlaLeuValGlnAlaValLysAspLeuLysIleMetLysGluAla                                  655660665                                                                      AUGCUCGAUCUAAAUCGAAGACUGAGCAAGCUGGAAGGAAAGAAA2420                              MetLeuAspLeuAsnArgArgLeuSerLysLeuAspGlyLysLys                                  670675680                                                                      AGUGAUGGCCAGACUACUGAAGGGACAGCGGGAGAGCAACAACCG2465                              SerAspGlyGlnThrThrAspGlyThrAlaGlyGluGlnGlnPro                                  685690695                                                                      AUCCCUAAGACUCCAACUCGAGUGAAGGCAAGACCAGUUGUGAAG2510                              IleProLysThrProThrArgValLysAlaArgProValValLys                                  700705710                                                                      CAAUCAGGAACGAUAAUGGUAAACGAAGAGAGCACAGAAACUUUC2555                              GlnSerGlyThrIleMetValAsnAspGluSerThrAspThrPhe                                  715720725                                                                      AGGGAUAAUGAGAGUCGAGUGACUGACCCUAACAGGAGCGAUAUG2600                              ArgAspAsnGluSerArgValThrAspProAsnArgSerAspMet                                  730735740                                                                      UUUGCUGCUGUUACUGCAGAAUACUUAGUUAAAUCGUUUACAUGG2645                              PheAlaAlaValThrAlaAspTyrLeuValLysSerPheThrTrp                                  745750755                                                                      AAAGUUUCUGAUGGACAAGAUAAAGUUUUGGCUGACCUUGAUUUA2690                              LysValSerAspGlyGlnAspLysValLeuAlaAspLeuAspLeu                                  760765770                                                                      CCUCAAGACUUAUGGAAAUCCAAUUCCCGAUUGAGUGAUAUCAUG2735                              ProGlnAspLeuTrpLysSerAsnSerArgLeuSerAspIleMet                                  775780785                                                                      GGGUAUUUCCAAUAUUAUGAUGCAACCGGAAUCACUUUUCGCAUA2780                              GlyTyrPheGlnTyrTyrAspAlaThrGlyIleThrPheArgIle                                  790795800                                                                      ACGACAACAUGUGUUCCUAUGCACGGUGGUACUUUAUGUGCUGCU2825                              ThrThrThrCysValProMetHisGlyGlyThrLeuCysAlaAla                                  805810815                                                                      UGGGAUGCUAAUGGUUGCGCUACACGACAAGGUAUAGCCACAACG2870                              TrpAspAlaAsnGlyCysAlaThrArgGlnGlyIleAlaThrThr                                  820825830                                                                      GUUCAGCUGACUGGUUUGCCCAAAACAUUUAUUGAAGCUCACAGC2915                              ValGlnLeuThrGlyLeuProLysThrPheIleAspAlaHisSer                                  835840845                                                                      UCAUCAGAAACGAUAAUCGUGGUAAAGAAUUCCAAUAUACAAUCC2960                              SerSerAspThrIleIleValValLysAsnSerAsnIleGlnSer                                  850855860                                                                      GCGAUUUGUCUAAGUGGAAGUGAGCACUCGUUUGGGAGAAUGGGA3005                              AlaIleCysLeuSerGlySerGluHisSerPheGlyArgMetGly                                  865870875                                                                      AUCCUGAAGAUCUGUUGCUUGAAUACGUUGAAUGCGCCAAAGGAA3050                              IleLeuLysIleCysCysLeuAsnThrLeuAsnAlaProLysAsp                                  880885890                                                                      GCUACACAGCAAGUGGCUGUGAACGUCUGGAUUAAGUUUGACGGA3095                              AlaThrGlnGlnValAlaValAsnValTrpIleLysPheAspGly                                  895900905                                                                      GUUAAAUUUCACGUUUAUUCUUUAAGGAAAAAUCCAGUCGUUUCG3140                              ValLysPheHisValTyrSerLeuArgLysAsnProValValSer                                  910915920                                                                      CAACUGCAGGUGGCAUCUCUUACAGACAUAGGAGAAUUGAGCAGU3185                              GlnLeuGlnValAlaSerLeuThrAspIleGlyAspLeuSerSer                                  925930935                                                                      GUGGUUGCUACUGGUUCUUGGUCUACUACCUCGGCUACUAAUUUG3230                              ValValAlaThrGlySerTrpSerThrThrSerAlaThrAsnLeu                                  940945950                                                                      AUGGAAUUAAACAUUCAUCCCACCUCCUGUGCUAUUCAGAACGGA3275                              MetAspLeuAsnIleHisProThrSerCysAlaIleGlnAsnGly                                  955960965                                                                      UUGAUAACACAGACACCAUUGAGUGUUUUAGCUCAUGCUUUUGCA3320                              LeuIleThrGlnThrProLeuSerValLeuAlaHisAlaPheAla                                  970975980                                                                      AGGUGGAGAGGAUCGUUGAAAAUUUCCAUCAUUUUCGGAGCGAGU3365                              ArgTrpArgGlySerLeuLysIleSerIleIlePheGlyAlaSer                                  985990995                                                                      UUGUUUACCCGAGGACGAAUCUUAGCCGCUGCUGUGCCCGUUGCU3410                              LeuPheThrArgGlyArgIleLeuAlaAlaAlaValProValAla                                  100010051010                                                                   AAGCGCAAAGGUACCAUGAGCCUUGACGAGAUUAGUGGGUAUCAU3455                              LysArgLysGlyThrMetSerLeuAspGluIleSerGlyTyrHis                                  101510201025                                                                   AAUGUUUGCUGCUUAUUGAAUGGUCAGCAAACUACAUUUGAAUUG3500                              AsnValCysCysLeuLeuAsnGlyGlnGlnThrThrPheAspLeu                                  103010351040                                                                   GAAAUCCCAUAUUAUUCUGUGGGCCAAGAUUCUUUCGUGUACCGU3545                              AspIleProTyrTyrSerValGlyGlnAspSerPheValTyrArg                                  104510501055                                                                   GAUGCUCUUUUUGAUAUCUCUGCGCACGAUGGGAAUUUUAUGAUU3590                              AspAlaLeuPheAspIleSerAlaHisAspGlyAsnPheMetIle                                  106010651070                                                                   ACUCGCUUGCAUCUCGUGAUACUGGAUAAAUUGGUAAUGAGCGCU3635                              ThrArgLeuHisLeuValIleLeuAspLysLeuValMetSerAla                                  107510801085                                                                   AAUGCGAGCAACAGCAUAAAUUUUUCCGUGACUCUUGGACCAGGU3680                              AsnAlaSerAsnSerIleAsnPheSerValThrLeuGlyProGly                                  109010951100                                                                   UCUGAUUUGGAAUUGAAAUAUCUUGCAGGAGUACAUGGGCAGCGC3725                              SerAspLeuAspLeuLysTyrLeuAlaGlyValHisGlyGlnArg                                  110511101115                                                                   AUAGUCCGCGAGUUGAAGAUGCAGGUUUCAUUGGGUCGGUCAUUU3770                              IleValArgGluLeuLysMetGlnValSerLeuGlyArgSerPhe                                  112011251130                                                                   GAGAAUGGAGUGCUUAUUGGUAGUGGCUUCGACGACUUGCUACAA3815                              GluAsnGlyValLeuIleGlySerGlyPheAspAspLeuLeuGln                                  113511401145                                                                   AGAUGGAGUCAUUUGGUGUCCAUGCCUUUUAAUGCAAAAGGAGAC3860                              ArgTrpSerHisLeuValSerMetProPheAsnAlaLysGlyAsp                                  115011551160                                                                   AGCGAUGAGAUCCAAGUCUUUGGCUAUAUCAUGACUGUUGCCCCG3905                              SerAspGluIleGlnValPheGlyTyrIleMetThrValAlaPro                                  116511701175                                                                   GCGUAUCGUUCCCUUCCAGUCCACUGCACGCUGCUAAGUUGGUUU3950                              AlaTyrArgSerLeuProValHisCysThrLeuLeuSerTrpPhe                                  118011851190                                                                   UCACAAUUAUUCGUGCAGUGGAAAGGUGGUAUAAAGUAUAGACUA3995                              SerGlnLeuPheValGlnTrpLysGlyGlyIleLysTyrArgLeu                                  119512001205                                                                   CACAUUGAUUCAGAAGAGCGCAGAUGGGGUGGAUUCAUCAAAGUU4040                              HisIleAspSerAspGluArgArgTrpGlyGlyPheIleLysVal                                  121012151220                                                                   UGGCAUGACCCAAAUGGCUCUUUGGAUGAAGGGAAAGAAUUUGCU4085                              TrpHisAspProAsnGlySerLeuAspAspGlyLysAspPheAla                                  122512301235                                                                   AAAGCGGAUAUUCUAUCGCCACCAGCCGGAGCUAUGGUUCGUUAU4130                              LysAlaAspIleLeuSerProProAlaGlyAlaMetValArgTyr                                  124012451250                                                                   UGGAACUAUUUAAAUGGAGACUUGGAGUUUACAGUACCAUUUUGU4175                              TrpAsnTyrLeuAsnGlyAspLeuGluPheThrValProPheCys                                  125512601265                                                                   GCUAGAACCAGUACGCUGUUCAUACCAAAAGCUAUGAUUGCCACC4220                              AlaArgThrSerThrLeuPheIleProLysAlaMetIleAlaThr                                  127012751280                                                                   GAUUCAAAGUCAUGGAUUCUGAACUACAACGGUACAUUGAAUUUC4265                              AspSerLysSerTrpIleLeuAsnTyrAsnGlyThrLeuAsnPhe                                  128512901295                                                                   GCGUACCAAGGAGUAGAUGACUUCACAAUUACAGUGGAAACAAGU4310                              AlaTyrGlnGlyValAspAspPheThrIleThrValAspThrSer                                  130013051310                                                                   GCAGCCGACGACUUUGAAUUUCACGUUCGAACAGUUGCACCCCGC4355                              AlaAlaAspAspPheAspPheHisValArgThrValAlaProArg                                  131513201325                                                                   GCUGGAAAGGUCAACGAAGCUUUUGCCAAAUUGGAGUACGCUUCU4400                              AlaGlyLysValAsnAspAlaPheAlaLysLeuGluTyrAlaSer                                  133013351340                                                                   GAUUUAAAGGAUAUCAAAGAAUCUCUGACAUCUUCCACUCGUUUG4445                              AspLeuLysAspIleLysAspSerLeuThrSerSerThrArgLeu                                  134513501355                                                                   AAAGGGCCUCAUUAUAAAACGAAAAUUACCUCAAUAGAGCCAAAU4490                              LysGlyProHisTyrLysThrLysIleThrSerIleGluProAsn                                  136013651370                                                                   AAAAUUGAUGAAAAUGAGUCCUCACGUGGUAAAGAUAACAAGUCA4535                              LysIleAspAspAsnGluSerSerArgGlyLysAspAsnLysSer                                  137513801385                                                                   AAUUCGAAAUUUGAGGACUUACUCAAUGCAACAGCUCAGAUGGAU4580                              AsnSerLysPheGluAspLeuLeuAsnAlaThrAlaGlnMetAsp                                  139013951400                                                                   UUUGAUCGAGCCACAGCGAACGUUGGGUGUGUGCCAUUCUCCAUU4625                              PheAspArgAlaThrAlaAsnValGlyCysValProPheSerIle                                  140514101415                                                                   GCAAAGACAGCAAAGGUGCUUUCGGAACGCGAGACGUGUAAGAAG4670                              AlaLysThrAlaLysValLeuSerAspArgGluThrCysLysLys                                  142014251430                                                                   AUGGCAGAUGUGUUAGAUUUCACACACUCAUGUUUGAACUUAGAC4715                              MetAlaAspValLeuAspPheThrHisSerCysLeuAsnLeuAsp                                  143514401445                                                                   AGUCAACCUGCGGCGGCAAGAUUAGCAGCGGCCAUUUCUCAAAUA4760                              SerGlnProAlaAlaAlaArgLeuAlaAlaAlaIleSerGlnIle                                  150015051510                                                                   GCACCUAUUAUGGAGAGCAUCGGUAGAACCACUCAAAGCGUAGAG4805                              AlaProIleMetGluSerIleGlyArgThrThrGlnSerValGlu                                  151515201525                                                                   GAAAAAUUGGCUUCUGUGGAUACAUUUAGGGACAAAAUCAUGGCU4850                              AspLysLeuAlaSerValAspThrPheArgAspLysIleMetAla                                  153015351540                                                                   CUAAUUUCAAACGUGCUUGGGGAUACUCUACCUGGACUGGCCAUU4895                              LeuIleSerAsnValLeuGlyAspThrLeuProGlyLeuAlaIle                                  154515501555                                                                   GCUGACUUCAAAAAAGGAAAAUAUGUGUGGGCCUCGUUCCUGACA4940                              AlaAspPheLysLysGlyLysTyrValTrpAlaSerPheLeuThr                                  160016051610                                                                   AUGAUAGCCGCUUGCGUAGUAGCUUGGGCUGCCACUAGCAAGAAA4985                              MetIleAlaAlaCysValValAlaTrpAlaAlaThrSerLysLys                                  161516201625                                                                   AGCUUCUUGAAAAGAUUUGCAGUGGUAGCUAUGAUAAUUUGGAGC5030                              SerPheLeuLysArgPheAlaValValAlaMetIleIleTrpSer                                  163016351640                                                                   CCAUUUCUCGCAAGUAAAAUAUGGGCGCUUGGUACAUGGAUUAGG5075                              ProPheLeuAlaSerLysIleTrpAlaLeuGlyThrTrpIleArg                                  164516501655                                                                   AAGAGCUGGAGUAAGCUUUGGCCUAAGUCAGACUCAUGCCGACAA5120                              LysSerTrpSerLysLeuTrpProLysSerAspSerCysArgGln                                  166016651670                                                                   CACUCUUUGGCAGGCCUGUGUGAAAGUGUGUUCACAUCAUUCAAG5165                              HisSerLeuAlaGlyLeuCysAspSerValPheThrSerPheLys                                  167516801685                                                                   GAUUUCCCUGACUGGUUUAAAUCAGGAGGAAUCACGAUUGUGACG5210                              AspPheProAspTrpPheLysSerGlyGlyIleThrIleValThr                                  169016951700                                                                   CAAGUUUGCACAGUAUUACUGACGAUAGUGAGUCUGAUUACACUU5255                              GlnValCysThrValLeuLeuThrIleValSerLeuIleThrLeu                                  170517101715                                                                   GGAACUAUACCAAGCACGAAACAAAAUGCUACGUUCGCAGACAAA5300                              GlyThrIleProSerThrLysGlnAsnAlaThrPheAlaAspLys                                  172017251730                                                                   UUUAAAGAAUUUGGUAACAUGAGCAGAGCUACAACGUCAAUAGCU5345                              PheLysAspPheGlyAsnMetSerArgAlaThrThrSerIleAla                                  173517401745                                                                   GCAGGUUACAAGACGAUAUCAGAGCUGUGUUCGAAAUUCACCAAU5390                              AlaGlyTyrLysThrIleSerGluLeuCysSerLysPheThrAsn                                  175017551760                                                                   UACUUGGCUGUAACCUUCUUUGGGGCGCAAGUUGAUGACGAUGCU5435                              TyrLeuAlaValThrPhePheGlyAlaGlnValAspAspAspAla                                  176517701775                                                                   UUCAAGGGUUUGGUAGCGUUCAACGUUAAGGAAUGGAUUCUUGAA5480                              PheLysGlyLeuValAlaPheAsnValLysAspTrpIleLeuAsp                                  178017851790                                                                   GUGAAAAACCUGUCUCUUGAGGAAAACAAAUUUAGUGGUUUUGGU5525                              ValLysAsnLeuSerLeuGluAspAsnLysPheSerGlyPheGly                                  179518001805                                                                   GGUGAUGAGCAUCUUGUCAAGGUUAGACAUUUAUAUGAUAAAUCU5570                              GlyAspGluHisLeuValLysValArgHisLeuTyrAspLysSer                                  181018151820                                                                   GUGGAAAUAACCUAUAAGUUGCUCCAGAAAAAUCGAGUUCCCAUU5615                              ValAspIleThrTyrLysLeuLeuGlnLysAsnArgValProIle                                  182518301835                                                                   GCUAUGCUUCCUAUCAUCCGAGACACGUGUAAGAAGUGCGAGGAU5660                              AlaMetLeuProIleIleArgAspThrCysLysLysCysGluAsp                                  184018451850                                                                   UUGCUAAACGAGAGUUAUACUUACAAAGGUAUGAAAACUCCGCGC5705                              LeuLeuAsnGluSerTyrThrTyrLysGlyMetLysThrProArg                                  185518601865                                                                   GUGGACCCAUUCUAUAUAUGCCUUUUUGGAGCACCUGGAGUUGGC5750                              ValAspProPheTyrIleCysLeuPheGlyAlaProGlyValGly                                  187018751880                                                                   AAGUCCACAGUGGCAUCGAUGAUUGUUGACGAUUUGUUGGAUGCU5795                              LysSerThrValAlaSerMetIleValAspAspLeuLeuAspAla                                  188518901895                                                                   AUGGGCGAACCUAAGGUUGAUAGGAUCUAUACGCGAUGCUGUUCU5840                              MetGlyAspProLysValAspArgIleTyrThrArgCysCysSer                                  190019051910                                                                   GAUCAAUAUUGGAGCAAUUAUCACCACGAGCCAGUUAUUUGUUAU5885                              AspGlnTyrTrpSerAsnTyrHisHisGluProValIleCysTyr                                  191519201925                                                                   GACGACUUGGGGGCAAUCAGCAGACCAGCGAGUUUAUCAGACUAU5930                              AspAspLeuGlyAlaIleSerArgProAlaSerLeuSerAspTyr                                  193019351940                                                                   GGGGAGAUAAUGGGAAUCAAAUCGAACAGACCAUACUCCCUACCU5975                              GlyGluIleMetGlyIleLysSerAsnArgProTyrSerLeuPro                                  194519501955                                                                   AUGGCUGCUGUUGAUGAGAAAGGAAGGCAUUGUUUAUCGCGAUAC6020                              MetAlaAlaValAspGluLysGlyArgHisCysLeuSerArgTyr                                  196019651970                                                                   CUCAUUGCUUGUACAAAUUUAACCCAUCUGGACGAUACGGGCGAU6065                              LeuIleAlaCysThrAsnLeuThrHisLeuAspAspThrGlyAsp                                  197519801985                                                                   GUGAAAACAAAGGAUGCCUACUAUCGCAGAAUCAAUGUCCCAGUG6110                              ValLysThrLysAspAlaTyrTyrArgArgIleAsnValProVal                                  199019952000                                                                   ACAGUGACGAGAGAAGUAACCGCCAUGAUGAACCCCGAGGACCCA6155                              ThrValThrArgAspValThrAlaMetMetAsnProGluAspPro                                  200520102015                                                                   ACUGAUGGACUACGUUUCACCGUGGAGCAAGUGCUUGAUGGAGGU6200                              ThrAspGlyLeuArgPheThrValGluGlnValLeuAspGlyGly                                  202020252030                                                                   AGAUGGAUUAAUGUUACUGAAAGCCGUCUCCUCAAUGGAAGGAUG6245                              ArgTrpIleAsnValThrAspSerArgLeuLeuAsnGlyArgMet                                  203520402045                                                                   CCAUUCAGGGCUGAAGAUCUCAUGAACAUGAACUACAGUUACUUU6290                              ProPheArgAlaAspAspLeuMetAsnMetAsnTyrSerTyrPhe                                  205020552060                                                                   AUGGAGUUUCUCAAGAUGUAUGCUGCUUUAUAUAUGGAAAAUCAA6335                              MetGluPheLeuLysMetTyrAlaAlaLeuTyrMetAspAsnGln                                  206520702075                                                                   AACAUGUUGGUGGCAAAAUUGAGAGGAACAGAGAUCCCAGAAUCA6380                              AsnMetLeuValAlaLysLeuArgGlyThrGluIleProAspSer                                  208020852090                                                                   CGUAGUUCAGAGAAUGAAGAACUUGAAUUCGAUUAUUUGGCUACA6425                              ArgSerSerGluAsnAspAspLeuAspPheAspTyrLeuAlaThr                                  209521002105                                                                   GCUCAGAUGGACCAUACAGUGACAUUUGGGGAACUAGUUACCAAA6470                              AlaGlnMetAspHisThrValThrPheGlyAspLeuValThrLys                                  211021152120                                                                   UUCAACUCGUAUAAGCUUACUGGGAAACAAUGGAACAAGAGGCUC6515                              PheAsnSerTyrLysLeuThrGlyLysGlnTrpAsnLysArgLeu                                  212521302135                                                                   UGGGAACUUGGAUGGACAUCUCUAGACGGAUGGAACACGAACAAG6560                              CysAspLeuGlyTrpThrSerLeuAspGlyTrpAsnThrAsnLys                                  214021452150                                                                   AUUAUGAGAUUCGACGAUCUAGUUGCCGGAUUCUGUGGUUGCUCA6605                              IleMetArgPheAspAspLeuValAlaGlyPheCysGlyCysSer                                  215521602165                                                                   AGGAAUGAGAAUUGCAAUUUUGACUUCUAUCAUCAGAGACUUCAA6650                              ArgAsnGluAsnCysAsnPheAspPheTyrHisGlnArgLeuGln                                  217021752180                                                                   GCAUGUUUGAACAAGAAAGGGUUUGCUCCCGCAUAUCAAUAUUUC6695                              AlaCysLeuAsnLysLysGlyPheAlaProAlaTyrGlnTyrPhe                                  218521902195                                                                   AACCUUCACAAGUUGAAUUCAGACACCCAGAAGACAGAGCUCAAG6740                              AsnLeuHisLysLeuAsnSerAspThrGlnLysThrGluLeuLys                                  220022052210                                                                   CUUAAAUGCGGGACAACUGCUGAAGAUUUAUUCAGACAAGCUGAC6785                              LeuLysCysGlyThrThrAlaAspAspLeuPheArgGlnAlaAsp                                  221522202225                                                                   UUGAUGGUCAUAUUCUCCUACCUCUUAUUUGUUGCGAGAAUUGGG6830                              LeuMetValIlePheSerTyrLeuLeuPheValAlaArgIleGly                                  223022352240                                                                   GUGAGUGGAUCUCAUGUGUGUCUGUCAUAUAACAUGUUGAACGUC6875                              ValSerGlySerHisValCysLeuSerTyrAsnMetLeuAsnVal                                  224522502255                                                                   AAGGAUGUCAAGGAUUUUGAGAUAUGCAGGGAGAACGUUCUUGAU6920                              LysAspValLysAspPheGluIleCysArgGluAsnValLeuAsp                                  226022652270                                                                   UUGUCCAGAAAAACUACAAUCGACGGUGAAGAAUGCUAUAUCUGG6965                              LeuSerArgLysThrThrIleAspGlyAspAspCysTyrIleTrp                                  227522802285                                                                   AAUUUUAUUUCUGAUAUCUUCCCACGCAUUGUGGCUAAGUACAAC7010                              AsnPheIleSerAspIlePheProArgIleValAlaLysTyrAsn                                  229022952300                                                                   UGUGUUGUGCUUAACGACGGAGAGAAGAGAUACAUCUUCGUGACU7055                              CysValValLeuAsnAspGlyGluLysArgTyrIlePheValThr                                  230523102315                                                                   GACAGCGCGCCCACUAGGAUCUUUCCCGAUUUGGCUUGGUCAGAU7100                              AspSerAlaProThrArgIlePheProAspLeuAlaTrpSerAsp                                  232023252330                                                                   CUUAUUUCCGGCAAGCAAGUUGUGAGUCCAAACAUUAUCAAAGUG7145                              LeuIleSerGlyLysGlnValValSerProAsnIleIleLysVal                                  233523402345                                                                   GCUGGAGAAACCAAGUCGAAAACCAUUGCCCCUCUGCUAGCAGAU7190                              AlaGlyAspThrLysSerLysThrIleAlaProLeuLeuAlaAsp                                  235023552360                                                                   UCCUACAAGGUUUUCAAGGAUCCGAAGGCAUGGCUUGAGAGGAAC7235                              SerTyrLysValPheLysAspProLysAlaTrpLeuGluArgAsn                                  236523702375                                                                   AAAGAAUUGAAAGCAGCUCUAGAAACAGAAGAAUAUAUCGCUCUC7280                              LysAspLeuLysAlaAlaLeuAspThrAspAspTyrIleAlaLeu                                  238023852390                                                                   CUCUUUGCUGUUGCAUGUGAAGCUGGUAGAUUCACUCAAAUUUUA7325                              LeuPheAlaValAlaCysAspAlaGlyArgPheThrGlnIleLeu                                  239524002405                                                                   GACAAACCUCCCAGUAGACGCAAGAUUUUAAAUAUGUCCGAAAGG7370                              AspLysProProSerArgArgLysIleLeuAsnMetSerAspArg                                  241024152420                                                                   UAUAAUGCAUAUAUUGAACAGGAAAAAGGGCUGAUUGGGAGACUU7415                              TyrAsnAlaTyrIleAspGlnAspLysGlyLeuIleGlyArgLeu                                  242524302435                                                                   UCUAAACCAGCAAAGAUAUGCUUAGCCAUAGGAACUGGAGUUGCG7460                              SerLysProAlaLysIleCysLeuAlaIleGlyThrGlyValAla                                  244024452450                                                                   AUCUUUGGGGCCCUAGCAGGCAUUGGAGUGGGUUUGUUUAAGCUG7505                              IlePheGlyAlaLeuAlaGlyIleGlyValGlyLeuPheLysLeu                                  245524602465                                                                   AUAGCUCACUUCAACAAAGAUGAAGAAGAGGUAGACGAAAUUGAA7550                              IleAlaHisPheAsnLysAspAspAspGluValAspAspIleAsp                                  247024752480                                                                   UUUGAUAUACUCUCCCCAGAGAUGAGCGGUUCGCACGAAUCCGGC7595                              PheAspIleLeuSerProGluMetSerGlySerHisAspSerGly                                  248524902495                                                                   CAACAUACCACGAGGUACGUCACGAAGGAGCGAGUUCCAUCCAAA7640                              GlnHisThrThrArgTyrValThrLysGluArgValProSerLys                                  250025052510                                                                   CCAGCAAGGAGGCAACAUGAAUUUGAUCUAAUGUUCGAUAAUCUA7685                              ProAlaArgArgGlnHisAspPheAspLeuMetPheAspAsnLeu                                  251525202525                                                                   CCCACUCCACAAGUUGAAGAGCUAAAGAGUGAGAUGACCUGCGCC7730                              ProThrProGlnValAspGluLeuLysSerGluMetThrCysAla                                  253025352540                                                                   AGUGCCAGUGAUGAGCAUAAGACUCAGUAUGUUAAAAGAAGAGUG7775                              SerAlaSerAspGluHisLysThrGlnTyrValLysArgArgVal                                  254525502555                                                                   GGACCUGUAAGCAAACGUAAGGAUGCUUCGGUAGCAGAAAUUAGU7820                              GlyProValSerLysArgLysAspAlaSerValAlaAspIleSer                                  256025652570                                                                   GGAGCUCAUGCGAGUGAUCAGCAUCAUACAGAAUACUUGAAAGCA7865                              GlyAlaHisAlaSerAspGlnHisHisThrAspTyrLeuLysAla                                  257525802585                                                                   CGCGUUCCACUCAUGAAAAGAAUAGCUACCAAAGAGAGCUAUGUU7910                              ArgValProLeuMetLysArgIleAlaThrLysGluSerTyrVal                                  259025952600                                                                   GUAACUUACGAUGACGAACCCAGCUCUCAUAUUUCCCUAGUUCGC7955                              ValThrTyrAspAspAspProSerSerHisIleSerLeuValArg                                  260526102615                                                                   AGGAUCCGACGUACACGACUGGCAAGAGCCAUCAAGCAAAUGGCA8000                              ArgIleArgArgThrArgLeuAlaArgAlaIleLysGlnMetAla                                  262026252630                                                                   GUCCUGGAGGACUUCCCAUCUACCUUGGAAGAGAUACGACUUUGG8045                              ValLeuGluAspPheProSerThrLeuAspGluIleArgLeuTrp                                  263526402645                                                                   AGACAAAACGCUGCAAAUAAAGGGGUUAUUGUUCCGAAGUACUCA8090                              ArgGlnAsnAlaAlaAsnLysGlyValIleValProLysTyrSer                                  265026552660                                                                   ACAAGUGGGAAAUUCUUCAGUGGCUUGUUGGAUGAUGAAGAAGAA8135                              ThrSerGlyLysPhePheSerGlyLeuLeuAspAspAspAspAsp                                  266526702675                                                                   GAACCUCAGAAUGUGAAUAUGUUGAACGAAGAGGACAUUGAGGUA8180                              AspProGlnAsnValAsnMetLeuAsnAspGluAspIleGluVal                                  268026852690                                                                   GAUAAGCGAAUGUUUGAGAAGAUUUCUGAGGUUAUAAGCGUGAUU8225                              AspLysArgMetPheGluLysIleSerGluValIleSerValIle                                  269527002705                                                                   CAACCCAGAAAGAAUGAGCUGGAAAGAAUGAUUGAGGAAGGCGUA8270                              GlnProArgLysAsnGluLeuAspArgMetIleGluAspGlyVal                                  271027152720                                                                   CACCACAAGGUCGUAAAGCAGGCAAGGGUUAACGACAAGGGCUUA8315                              HisHisLysValValLysGlnAlaArgValAsnAspLysGlyLeu                                  272527302735                                                                   GCCAAAGACCCCAACAUGGUGACUAUCUUGACGGACAAAUUAAUU8360                              AlaLysAspProAsnMetValThrIleLeuThrAspLysLeuIle                                  274027452750                                                                   AAUAUUAGUGCGGUGAUCGUCAAUUUAACGCCGACACGCCGGGCA8405                              AsnIleSerAlaValIleValAsnLeuThrProThrArgArgAla                                  275527602765                                                                   UACAUGAACGUGGUACGUCUUAUAGGCACUAUAGUUGUUUGCCCA8450                              TyrMetAsnValValArgLeuIleGlyThrIleValValCysPro                                  277027752780                                                                   GCCCACUACUUGGAAGCUUUAGAGGAAGGAGAUGAGCUGUAUUUC8495                              AlaHisTyrLeuAspAlaLeuGluAspGlyAspGluLeuTyrPhe                                  278527902795                                                                   AUUUGCUUCUCAUUGGUUAUCAAGCUCACUUUUGAUCCAAGUAGA8540                              IleCysPheSerLeuValIleLysLeuThrPheAspProSerArg                                  280028052810                                                                   GUGACUCUCGUGAAUAGCCAGCAGGAUUUGAUGGUUUGGGAUCUU8585                              ValThrLeuValAsnSerGlnGlnAspLeuMetValTrpAspLeu                                  281528202825                                                                   GGGAACAUGGUACCACCCUCAAUUGAUACUCUUAAAAUGAUACCU8630                              GlyAsnMetValProProSerIleAspThrLeuLysMetIlePro                                  283028352840                                                                   ACGCUUGAAGACUGGGAUCACUUUCAGGAUGGACCAGGAGCCUUU8675                              ThrLeuAspAspTrpAspHisPheGlnAspGlyProGlyAlaPhe                                  284528502855                                                                   GCUGUUACGAAAUAUAACUCGAAAUUCCCAACCAAUUAUAUCAAC8720                              AlaValThrLysTyrAsnSerLysPheProThrAsnTyrIleAsn                                  286028652870                                                                   ACACUGACUAUGAUUGAGAGGAUUAGGGCAAAUACUCAGAAUCCC8765                              ThrLeuThrMetIleGluArgIleArgAlaAsnThrGlnAsnPro                                  287528802885                                                                   ACGGGUUGUUAUUCCAUGAUGGGCUCCCAACAUACAAUCACCACA8810                              ThrGlyCysTyrSerMetMetGlySerGlnHisThrIleThrThr                                  289028952900                                                                   GGAUUGCGAUAUCAAAUGUUCUCUCUUGAUGGAUUCUGCGGUGGG8855                              GlyLeuArgTyrGlnMetPheSerLeuAspGlyPheCysGlyGly                                  290529102915                                                                   UUAAUCCUGAGAGCCAGCACAAACAUGGUGAGAAAGGUCGUCGGG8900                              LeuIleLeuArgAlaSerThrAsnMetValArgLysValValGly                                  292029252930                                                                   AUCCACGUUGCUGGAAGCCAGAAUCACGCUAUGGGAUAUGCAGAG8945                              IleHisValAlaGlySerGlnAsnHisAlaMetGlyTyrAlaGlu                                  293529402945                                                                   UGCCUUAUUGCAGAAGAUUUACGGGCUGCAGUGGCGAGAUUGGCG8990                              CysLeuIleAlaAspAspLeuArgAlaAlaValAlaArgLeuAla                                  295029552960                                                                   CUAGAUCCUAGAAGCACCAUCCAGGCAAGUCUGAAAGGUAGGAUU9035                              LeuAspProArgSerThrIleGlnAlaSerLeuLysGlyArgIle                                  296529702975                                                                   GAUGCUGUUUCUAAACAAUGUGGUUUAGACAGAGCUCUGGGUACG9080                              AspAlaValSerLysGlnCysGlyLeuAspArgAlaLeuGlyThr                                  298029852990                                                                   AUAGGAUGUCACGGGAAAGUUGCCUCUGAAGAUAUUACAAGUGCC9125                              IleGlyCysHisGlyLysValAlaSerAspAspIleThrSerAla                                  299530003005                                                                   GCCACGAAAACUUCCAUAAGAAAGUCAAGAAUACAUGGUCUAGUG9170                              AlaThrLysThrSerIleArgLysSerArgIleHisGlyLeuVal                                  301030153020                                                                   GGUGAGAUUAGAACUGAGCCUUCAAUUUUACACGCUCAUGAUCCC9215                              GlyGluIleArgThrGluProSerIleLeuHisAlaHisAspPro                                  302530303035                                                                   CGACUGCCUAAAGACAAGAUUGGGAAAUGGGACCCGGUUAUUGAG9260                              ArgLeuProLysAspLysIleGlyLysTrpAspProValIleGlu                                  304030453050                                                                   GCAUCAAUGAAGUAUGGUUCGAGAAUCACACCGUUCCCUGUAGAC9305                              AlaSerMetLysTyrGlySerArgIleThrProPheProValAsp                                  305530603065                                                                   CAAAUUCUGGAAGUGGAGGAUCAUCUUUCUAAAAUGUUGGCCAAU9350                              GlnIleLeuAspValGluAspHisLeuSerLysMetLeuAlaAsn                                  307030753080                                                                   UGUGAGAAUUCAAAAAACAAGCGGCAGGUUAAUAAUCUAGAAAUA9395                              CysGluAsnSerLysAsnLysArgGlnValAsnAsnLeuAspIle                                  308530903095                                                                   GGGAUUAAUGGAAUUGACCAGUCGGAUUAUUGGCAACAGAUAGAA9440                              GlyIleAsnGlyIleAspGlnSerAspTyrTrpGlnGlnIleAsp                                  310031053110                                                                   AUGGAUACUUCAAGUGGUUGGCCAUACGCUAAGCGUAAACCUGUU9485                              MetAspThrSerSerGlyTrpProTyrAlaLysArgLysProVal                                  311531203125                                                                   GGGGCAGCUGGAAAGAAAUGGCUAUUCGAGCAAGACGGCACAUAU9530                              GlyAlaAlaGlyLysLysTrpLeuPheGluGlnAspGlyThrTyr                                  313031353140                                                                   CCCUCCGGAAAACCUCGAUAUGUAUUUGGAGAUGCCGGGUUGAUU9575                              ProSerGlyLysProArgTyrValPheGlyAspAlaGlyLeuIle                                  314531503155                                                                   GAGAGCUAUAACUCGAUGCUUGGUGAGGCGAAGCAAGGCAUUAGU9620                              GluSerTyrAsnSerMetLeuGlyGluAlaLysGlnGlyIleSer                                  316031653170                                                                   CCCACUGUCGUCACAAUUGAGUGCGCAAAAGAUGAGAGGCGGAAG9665                              ProThrValValThrIleGluCysAlaLysAspGluArgArgLys                                  317531803185                                                                   CUUAAUAAGAUAUAUGAGAAACCCGCCACUCGGACGUUCACCAUA9710                              LeuAsnLysIleTyrGluLysProAlaThrArgThrPheThrIle                                  319031953200                                                                   CUGCCACCUGAGAUUAAUAUUUUAUUCAGGCAGUAUUUCGGAGAU9755                              LeuProProGluIleAsnIleLeuPheArgGlnTyrPheGlyAsp                                  320532103215                                                                   UUUGCAGCGAUGGUAAUGACAUGUAGAGCCAAGCUUUUCUGUCAA9800                              PheAlaAlaMetValMetThrCysArgAlaLysLeuPheCysGln                                  322032253230                                                                   GUUGGCAUCAACCCAGAGUCAAUGGAGUGGGGUGAUCUCAUGCUA9845                              ValGlyIleAsnProGluSerMetGluTrpGlyAspLeuMetLeu                                  323532403245                                                                   GGUCUAAAGGAGAAAUCAACUAAGGGAUUUGCAGGAGAUUAUUCG9890                              GlyLeuLysGluLysSerThrLysGlyPheAlaGlyAspTyrSer                                  325032553260                                                                   AAGUUCGAUGGAAUCGGAGACCCCCAGAUUUAUCAUUCAAUUACC9935                              LysPheAspGlyIleGlyAspProGlnIleTyrHisSerIleThr                                  326532703275                                                                   CAAGUAGUCAACAACUGGUAUAACGAUGGGGAAGAAAAUGCGACU9980                              GlnValValAsnAsnTrpTyrAsnAspGlyAspAspAsnAlaThr                                  328032853290                                                                   AUCAGGCAUGCUCUGAUAAGUAGCAUUAUACACAGGCGGGGCAUU10025                             IleArgHisAlaLeuIleSerSerIleIleHisArgArgGlyIle                                  329533003305                                                                   GUGAAAGAAUAUUUGUUCCAGUAUUGCCAGGGUAUGCCAUCAGGG10070                             ValLysAspTyrLeuPheGlnTyrCysGlnGlyMetProSerGly                                  331033153320                                                                   UUCGCCAUGACAGUGAUAUUCAAUUCGUUUAUGAACUAUUAUUAU10115                             PheAlaMetThrValIlePheAsnSerPheMetAsnTyrTyrTyr                                  332533303335                                                                   CUGUCUUUGGCCUGGAUGAAUCUGAUAAGUGCAUCCCCCCUUAGU10160                             LeuSerLeuAlaTrpMetAsnLeuIleSerAlaSerProLeuSer                                  334033453350                                                                   CCACAAGCUUCUUUGAGAUAUUUUGAUGAGUAUUGUAAGGUCAUU10205                             ProGlnAlaSerLeuArgTyrPheAspGluTyrCysLysValIle                                  335533603365                                                                   GUUUACGGUGAUGAUAAUAUUGUUGCCGUCAACGAAGAAUUCUUA10250                             ValTyrGlyAspAspAsnIleValAlaValAsnAspAspPheLeu                                  337033753380                                                                   GAGUACUAUAACUUGAGGCUUGUGGCAGGCUAUCUUAGUCAAUUU10295                             GluTyrTyrAsnLeuArgLeuValAlaGlyTyrLeuSerGlnPhe                                  338533903395                                                                   GGAGUAAGCUACACUGAUGACGCCAAGAACCCAAUAGAGAAGAGC10340                             GlyValSerTyrThrAspAspAlaLysAsnProIleGluLysSer                                  340034053410                                                                   GAACGAUAUGUGAAGAUAGAAGACGUUACGUUCUUAAAACGGCGA10385                             AspArgTyrValLysIleAspAspValThrPheLeuLysArgArg                                  341534203425                                                                   UGGGUGAGUCUUGGCGGUAGAGCUUCGAUGCUGUACAAAGCUCCG10430                             TrpValSerLeuGlyGlyArgAlaSerMetLeuTyrLysAlaPro                                  343034353440                                                                   CUUGACAAGGUUAGCAUUGAGGAAAGGCUUAACUGGAUCAGAGAG10475                             LeuAspLysValSerIleGluAspArgLeuAsnTrpIleArgGlu                                  344534503455                                                                   UGUGACGAUGGGGAACUAGCUCUGGUGCAGAACAUUGAAAGUGCU10520                             CysAspAspGlyAspLeuAlaLeuValGlnAsnIleAspSerAla                                  346034653470                                                                   CUGUACGAAGCUAGUAUUCAUGGCCACACAUAUUUUGGAGAGCUU10565                             LeuTyrAspAlaSerIleHisGlyHisThrTyrPheGlyGluLeu                                  347534803485                                                                   AAAGAUAAAAUUGCUAAAGCCUGUGAUGCAGUCAUGAUAACUAUG10610                             LysAspLysIleAlaLysAlaCysAspAlaValMetIleThrMet                                  349034953500                                                                   CCAAAUAUAAGAUAUAUUGACUGCCAGAGACGAUGGUGGACCUCC10655                             ProAsnIleArgTyrIleAspCysGlnArgArgTrpTrpThrSer                                  350535103515                                                                   AUGACUGGUGGGUAUCUUGAGCCGUCUGAUGUCACCAAACUUGUA10700                             MetThrGlyGlyTyrLeuGluProSerAspValThrLysLeuVal                                  352035253530                                                                   AGGCUUGUUGAGAAAGGACUACUAGACCCGAAAUCAGUAUGGAAA10745                             ArgLeuValGluLysGlyLeuLeuAspProLysSerValTrpLys                                  353535403545                                                                   GACCCAUUGUACAGAACCAACAAGUUGCUAUUCGACCUAUUGAGG10790                             AspProLeuTyrArgThrAsnLysLeuLeuPheAspLeuLeuArg                                  355035553560                                                                   GAGGUUAAGGCAGCACCCCUGGCCGCAUUUGUGGUCUAA10829                                   GluValLysAlaAlaProLeuAlaAlaPheValVal                                           35653570                                                                       GUUACCCUUCUGACAAAAGGGCCUUGAACGGUUAUGGUUGAACAGAACUG10879                        UAAAAGGUGAGGACUAUAUAAGUUGUAGUACGGAUGAGAUUGAAAGAAAA10929                        UUGGGUCACUCCCAUUCCUUUAUUAGGAAGGAGUGAUACCUUUUGUGUAG10979                        AUCUCUACCCCGAAACUCUUGAACCCUCACACGUUUUGGAGUAACCAGUA11029                        CACCCUUUUAGGUGGACCCUCGACUAUAGAUCGAGACCAAGUAUUGACUU11079                        GGUGUUCACGUCUUGCCGGACGCAAAAUGGCACCCUUGUUUAGUGAUAUC11129                        AAGGUUACAAAUGUCACGCCCCACUAGUAAAAGUUUUGGUAUAUACGCAU11179                        UCGAACCGCCAAUGUAUACGUGUUUUCCCUUUUACUUUUUGUAUGUCGUC11229                        GUGGUGACGAGAUGCACGCCUGGUCAGCGGGGAAUAAGUUCACUAUAUGA11279                        ACAGACUCCGGCGAGCGAGACACGCUGUCGGCCUCGGGAGAGGGAACUAG11329                        CUCCAGGCACUUAAAUCCUGAAGUGUUAGAACUAAGCGUUUGAUCCUCCU11379                        CCGGGGGAAAGAGAACGCCAGUUCUUUAAGCCAUAACUCUAGUGAGUUGA11429                        AUCCUAUUCAUCCUUCUUAGGAUUAAGGAUUUCUGAAGUCUAUCAUGAAA11479                        AGUAGAUAGAAAGCAACACGUCAAUAACGUGGAACCUUUUCCGAGGAAGU11529                        AGGGUGCUUGUUCGAAAAUCAUGGUAGAUUCGGAAACAAUUUGCUUAGAG11579                        UGUGUCUUUUCGCGUUGGUAGUUCAACCGUUAGGGCUAGGCACACUUCUC11629                        CACGGGUUUGUGCUGCAGUAUUAAAUAUCAUUAAGGUACUGUGCUAUAGC11679                        GGAGAAAUUACAAAGCGUUGAACACAUUGACGAUGGGGCCCAAUGCGCAC11729                        CCGGAUGUGUUACGCACCGUUUUUCUCUGUGUCACUAUAGAUAAAAGUGG11779                        GGUAGC11785                                                                    (2) INFORMATION FOR SEQ ID NO: 5:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 45 bases                                                           (B) TYPE: nucleotide                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: viral RNA                                                  (A) DESCRIPTION: RNA codons for first 15 amino acids at                        5'end of MCDV coat protein 1 (CP1)                                             (iii) HYPOTHETICAL: No                                                         (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5:                                       GUUUCAUUGGGUCGGUCAUUUGAGAAUGGAGUGCUUAUUGGUAGU45                                ValSerLeuGlyArgSerPheGluAsnGlyValLeuIleGlySer                                  51015                                                                          (2) INFORMATION FOR SEQ ID NO: 6:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 15 amino acids                                                     (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (A) DESCRIPTION: first 15 amino acids of MCDV coat protein 3                   (iii) HYPOTHETICAL: No                                                         (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 6:                                       LeuGlnValAlaSerLeuThrAspIleGlyAspLeuSerSerVal                                  51015                                                                          (2) INFORMATION FOR SEQ ID NO: 7:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 15 amino acids                                                     (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (A) DESCRIPTION: first 15 amino acids of MCDV coat protein 1                   (iii) HYPOTHETICAL: No                                                         (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7:                                       ValSerLeuGlyArgSerPheGluAsnGlyValLeuIleGlySer                                  51015                                                                          __________________________________________________________________________ 

What is claimed is:
 1. A DNA clone coding substantially solely for a coat protein of maize chlorotic dwarf virus.
 2. An expression cassette comprising a DNA clone according to claim 1, operably linked to plant regulatory sequences which cause the expression of the DNA clone in plant cells.
 3. An expression cassette comprising a DNA clone according to claim 1, operably linked to bacterial expression regulatory sequences which cause the expression of the DNA clone in bacterial cells.
 4. Bacterial cells containing as a foreign plasmid at least one copy of an expression cassette according to claim
 3. 5. Transformed plant cells containing as foreign DNA at least one copy of the DNA sequence of an expression cassette according to claim
 2. 6. Transformed cells according to claim 5, further characterized in being cells of a monocotyledonous species.
 7. Transformed cells according to claim 6, further characterized in being maize, sorghum, wheat or rice cells.
 8. Transformed cells according to claim 5, further characterized in being cells of a dicotyledonous species.
 9. Transformed cells according to claim 8, further characterized in being soybean, alfalfa, tobacco or tomato cells.
 10. A maize cell or tissue culture comprising cells according to claim
 7. 11. A transformed maize plant, the cells of which contain as foreign DNA at least one copy of the DNA sequence of an expression cassette according to claim
 2. 12. A method of imparting resistance to maize chlorotic dwarf virus and maize dwarf mosaic virus-A to plants of a MCDV or MDMV-A susceptible taxon, comprising the steps of:a) culturing cells or tissues from at least one plant from the taxon, b) introducing into the cells of the cell culture or tissue culture at least one copy of an expression cassette comprising a DNA clone from the RNA genome of MCDV which codes substantially solely for the coat protein of the virus, operably linked to plant regulatory sequences which cause the expression of the DNA clone in the cells, and c) regenerating MCDV-resistant whole plants from the cell culture or tissue culture.
 13. A method according to claim 12 which comprises the further step of sexually or clonally reproducing the whole plants in such manner that at least one copy of the sequence provided by the expression cassette is present in the cells of progeny of the reproduction.
 14. A method according to claim 12 in which the expression cassette is introduced into the cells by electroporation.
 15. A method according to claim 12 in which the expression cassette is introduced into the cells by microparticle bombardment.
 16. A method according to claim 12 in which the expression cassette is introduced into the cells by microinjection.
 17. A method according to claim 13 for providing MCDV and MDMV-A resistance in Agrobacterium tumefaciens-susceptible dicotyledonous plants in which the expression cassette is introduced into the cells by infecting the cells with Agrobacterium tumefaciens, a plasmid of which has been modified to include the expression cassette.
 18. A method of imparting resistance to maize chlorotic dwarf virus and maize dwarf mosaic virus strain A to plants of a MCDV or MDMV-A susceptible taxon, comprising the steps of:a) selecting a fertile, MCDV resistant plant prepared by the method of claim 12 from a sexually compatible taxon; b) sexually crossing the MCDV resistant plant with a plant from the MCDV susceptible taxon; c) recovering reproductive material from the progeny of the cross; and d) growing resistant plants from the reproductive material.
 19. A method according to claim 18 which comprises the further steps of repetitively:a) backcrossing the MCDV resistant progeny with MCDV susceptible plants from the susceptible taxon; and b) selecting for expression of MCDV resistance among the progeny of the backcross,until the desired percentage of the characteristics of the susceptible taxon are present in the progeny along with MCDV resistance.
 20. A DNA molecule coding for maize chlorotic dwarf virus or a portion thereof which is capable of conferring resistance to maize chlorotic dwarf virus when expressed in a plant cell. 